Lens holder driving device capable of preventing deformation due to heat

ABSTRACT

A lens holder driving device includes a lens holder in which a lens assembly is mounted, a driving coil fixed to the lens holder at outside circumference thereof, a magnet opposite to the driving coil, a yoke including the magnet, an elastic member supporting the lens holder in a direction of an optical axis shiftably, and a base disposed at a lower side of the lens holder. The elastic member includes a lower elastic member which is disposed at a lower side of the lens holder and which includes first and second leaf spring pieces. The first and the second leaf spring pieces have first and second side portions which are electrically connected to first and second end portions of the driving coil by soldering, respectively. Each of the first and the second side portions has a side edge forming portion having a surface in which edges are formed.

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. JP 2012-017982, filed on Jan. 31, 2012,the disclosure of which is incorporated herein in its entirety byreference.

BACKGROUND OF THE INVENTION:

This invention relates to a lens holder driving device and, inparticular, to an autofocus lens holder driving device for use in acompact camera.

Camera-equipped cellular mobile phones mount compact cameras therein.The compact camera is provided with an autofocus lens holder drivingdevice. Previously, various autofocus lens holder driving devices havebeen proposed.

By way of illustration, Japanese Unexamined Patent ApplicationPublication No. 2009-251031 (JP-A-2009-251031) (which will be alsocalled Patent Document 1) discloses a lens driving device which iscapable of decreasing a parts count and of miniaturizing. The lensdriving device disclosed in Patent Document 1 comprises a lens holder inwhich a lens assembly can be mounted, a driving coil (a coil) fixed tothe lens holder at outside circumstance thereof, a magnet opposite tothe driving coil, an outer yoke including the magnet, an elastic member(an upper elastic member and a lower elastic member) for supporting thelens holder in a direction of an optical axis of the lens assemblyshiftably, and a base disposed at a lower side of the lens holder. InPatent Document 1, the elastic member (the upper elastic member and thelower elastic member) is disposed in the inside of the outer yoke. Theupper elastic member and the lower elastic member are called afront-side spring and a rear-side spring, respectively.

On the other hand, Japanese Unexamined Patent Application PublicationNo. 2009-014890 (JP-A-2009-014890) (which will be also called PatentDocument 2) discloses a lens driving device in which a coil is energizedfrom terminals through a rear-side spring. In the lens driving devicedisclosed in Patent Document 2, the rear-side spring comprises aring-shaped spring as a whole and comprises one side portion (half body)and another side portion (half body) which are divided into both sides.The one side portion and the other side portions are electricallyconnected to one end and another end of the coil by means of solder orthe like, respectively, thereby energizing to the coil from therear-side spring. The one side portion constituting the rear-side springis provided with a first terminal connection portion for connecting to afirst terminal (a first electrode terminal) while the other side portionconstituting the rear-side spring is provided with a second terminalconnection portion for connecting to a second terminal (a secondelectrode terminal). Each terminal connection portion has a flatsurface. One end (a tip) of the first terminal and the first terminalconnection portion are bonded by means of a conductive thermosettingadhesive while one end (a tip) of the second terminal and the secondterminal connection portion are bonded by means of a conductivethermosetting adhesive. Connections between the tips of the first andthe second terminals and the first and the second terminal connectionportions of the rear-side spring are not limited by the adhesive and maybe connections such as fit or the like.

In the above-mentioned lens driving device disclosed in Patent Document2, the one side portion of the rear-side spring is soldered to the oneend of the coil while the other side portion of the rear-side spring issoldered to the other end of the coil. The rear-side spring is held bythe lens holder. As a result, it is feared that the lens holder issusceptible to heat upon soldering (on electrically connecting the sideportions of the rear-side spring to the ends of the coil).

In addition, in the lens driving device disclosed in Patent Document 2,the tip of the first terminal is bonded to the first terminal connectionportion by means of the conductive thermosetting adhesive while the tipof the second terminal is bonded to the second connection portion bymeans of the conductive thermosetting adhesive. It is thereforedisadvantageous in that it is necessary to cure the conductivethermosetting adhesive by heating it and it requires in time and effort.In addition, the first and the second terminal connection portions ofthe rear-side spring are mounted on the base. Accordingly, it is fearedthat the base is susceptible to heat upon heating the conductivethermosetting adhesive (on electrically connecting the terminalconnection portions of the rear-side spring to the electrode terminals).

SUMMARY OF THE INVENTION:

It is therefore an exemplary object of the present invention to providea lens holder driving device which is capable of preventing a lensholder from deforming due to heat on electrically connecting sideportions of a rear-side spring (a lower elastic member) to end portionsof a driving coil.

It is therefore another exemplary object of the present invention toprovide a lens holder driving device which is capable of preventing abase from deforming due to heat on electrically connecting terminalconnection portions of a rear-side spring (a lower elastic member) toelectrode terminals.

Other objects of this invention will become clear as the descriptionproceeds.

On describing the gist of a first exemplary aspect of this invention, itis possible to be understood that a lens holder driving device comprisesa lens holder for holding a lens assembly, a driving coil which is fixedto the lens holder at outside circumference thereof and which has firstand second end portions, a magnet opposite to the driving coil, a yokeincluding the magnet, an elastic member supporting the lens holder in adirection of an optical axis of the lens assembly shiftably, and a basedisposed at a lower side of the lend holder. According to the firstexemplary aspect of this invention, the elastic member comprises a lowerelastic member disposed at a lower side of the lens holder. The lowerelastic member comprises first and second leaf spring pieces into whichthe lower elastic member is divided. The first and the second leafspring pieces have first and second side portions which are electricallyconnected to the first and the second end portions of the driving coilby soldering. Each of the first and the second side portions has a sideedge forming portion having a side surface in which edges are formed.

On describing the gist of a second exemplary aspect of this invention,it is possible to be understood that a lens holder driving devicecomprises a lens holder for holding a lens assembly, a driving coilwhich is fixed to the lens holder at outside circumference thereof, amagnet opposite to the driving coil, a yoke including the magnet, anelastic member supporting the lens holder in a direction of an opticalaxis of the lens assembly shiftably, and a base disposed at a lower sideof the lend holder. According to the second exemplary aspect of thisinvention, the elastic member comprises a lower elastic member disposedat a lower side of the lens holder. The lower elastic member comprisesfirst and second leaf spring pieces into which the lower elastic memberis divided. The lens holder driving device further comprises first andsecond electrode terminals for feeding the driving coil via the firstand the second leaf spring pieces. The first and the second leaf springpieces have first and second terminal connection portions which areelectrically connected to the first and the second electrode terminalsby soldering, respectively. Each of the first and the second terminalconnection portions has a connection edge forming portion having aconnection surface in which edges are formed.

BRIEF DESCRIPTION OF THE DRAWING:

FIG. 1 is a perspective view of a lens holder driving device accordingto an exemplary embodiment of the present invention;

FIG. 2 is an exploded perspective view of the lens holder driving deviceillustrated in FIG. 1;

FIG. 3 is a cross sectional view taken on line III-III of FIG. 1;

FIG. 4 is a cross sectional view taken on line IV-IV of FIG. 1;

FIG. 5 is a perspective view of a lens assembly mounted in the lensholder driving device illustrated in FIG. 1;

FIG. 6 is a perspective view of a image pickup device mounted on aprinted wiring board (PWB) that is mounted in the lens holder drivingdevice illustrated in FIG. 1;

FIG. 7 is a perspective view of a camera-equipped mobile terminal (asmart phone) in which the lens holder driving device illustrated in FIG.1 is mounted;

FIG. 8 is a bottom view of an outer yoke for use in the lens holderdriving device illustrated in FIG. 1;

FIG. 9 is a plan view of a lens holder for use in the lens holderdriving device illustrated in FIG. 1;

FIG. 10 is a side view of the lens holder illustrated in FIG. 9;

FIG. 11 is a bottom view of the lens holder illustrated in FIG. 9;

FIG. 12 is a plan view of the base for use in the lens holder drivingdevice illustrated in FIG. 1;

FIG. 13 is an explanation view showing stopper locations between theouter yoke and the lens holder;

FIG. 14 is an explanation view showing stopper locations between thelens holder and the base;

FIG. 15 is a perspective view of an inner yoke for use in the lensholder driving device illustrated in FIG. 1;

FIG. 16 is a perspective view of the lens holder for use in the lensholder driving device illustrated in FIG. 1;

FIG. 17 is a transverse sectional view of an assembly into which theinner yoke and the lens holder are assembled;

FIG. 18 is a perspective view of the lens holder illustrated in FIG. 16;

FIG. 19 is a perspective view of the base for use in the lens holderdriving device illustrated in FIG. 1;

FIG. 20 is a transverse sectional view of an assembly into which thelens holder and the base are assembled;

FIG. 21 is a perspective view of a lower elastic member disposed in thelens holder at the lower end thereof seen from a slanting below;

FIG. 22 is a partial enlarged perspective view enlargedly showing anarea where a second leaf spring piece of the lower elastic member shownin FIG. 21 is soldered to a second end portion of a driving coil bymeans of solder;

FIG. 23 is a perspective view showing a state where the outer yoke, aspacer, the upper electric member, and the inner yoke are removed fromthe lens driving device;

FIG. 24 is a partial enlarged perspective view enlargedly showing a partwhere a first leaf spring piece of the lower elastic member iselectrically connected to a first electrode terminal by means of solder;and

FIG. 25 is a partial enlarged perspective view enlargedly showing aconnected portion between the first leaf spring piece and the firstelectrode terminal before soldering by means of the solder in FIG. 24.

DESCRIPTION OF EMBODIMENTS

Referring to FIGS. 1 through 4, the description will proceed to a lensholder driving device 10 according to an exemplary embodiment of thisinvention. FIG. 1 is a perspective view of the lens holder drivingdevice 10 and FIG. 2 is an exploded perspective view of the lens holderdriving device 10. FIG. 3 is a cross-sectional view taken on lineIII-III of FIG. 1. FIG. 4 is a cross-sectional view taken on line IV-IVof FIG. 1. Herein, in the manner shown in FIGS. 1 through 4, anorthogonal coordinate system (X, Y, Z) is used. In a state illustratedin FIGS. 1 through 4, in the orthogonal coordinate system (X, Y, X), anX-axis direction is a fore-and-aft direction (a depth direction), aY-axis direction is a left-and-right direction (a width direction), anda Z-axis direction is an up-and-down direction (a height direction). Inaddition, in the example being illustrated in FIGS. 1 through 4, theup-and-down direction Z is a direction of an optical axis O of a lens.

However, in an actual use situation, the direction of the optical axisO, namely, the Z-axis direction becomes a fore-and-aft direction. Inother words, an upper direction of the Z-axis becomes a front directionwhile a lower direction of the Z-axis becomes a rear direction.

The illustrated lens holder driving device 10 is a lens holder drivingdevice comprising, as a driving source (a driving method), a drivingportion (a VCM method) of “moving coil method” using a voice coil motor(VCM).

The illustrated lens driving device 10 is mounted to a mobile terminalsuch as a camera-equipped cellular mobile phone which is enable toautomatic focusing, a smart phone, a notebook personal computer, atablet-type personal computer, a mobile-type game machine, a Web camera,a vehicle-mounted camera, or the like. The lens holder driving device 10is for moving the lens holder 14 (which will later be described) capableof mounting a lens assembly (a lens barrel) 11 as shown in FIG. 5 in thedirection of the optical axis O. The lens holder driving device 10comprises a base 12 which is disposed in a lower side (a rear side) inthe Z-axis direction (the direction of the optical axis O). The actuatorbase 12 has a lower portion (a rear portion) on which an image pickupdevice 13 disposed on a module board 34 (see, FIG. 23) is mounted, asshown in FIG. 6.

More specifically, as shown in FIG. 6, the image pickup device 13 ismounted on a printed wiring board (PWB) 35. That is, the printed wiringboard (PWB) 35 mounts other circuit elements (not shown) as well as theimage pickup device 13 thereon which constitute a printed circuit board(PCB). An infrared (IR) cut filter (not shown) is mounted in the moduleboard 34. The printed circuit board (PCB) is mounted to the base 12 viathe module board 34.

The image pickup device 13 picks up a subject image formed by the lensassembly 11 to convert it into an electric signal. The image pickupdevice 13 may, for example, comprise a CCD (charge coupled device) typeimage sensor, a CMOS (complementary metal oxide semiconductor) typeimage sensor, or the like. Accordingly, a camera module 40 comprises acombination of the lens holder driving device 10, the module board 34,and the image pickup device 13.

FIG. 7 is a perspective view showing appearance of a camera-equippedmobile terminal 50 on which the camera module 40 is mounted. Theillustrated camera-equipped mobile terminal 50 comprises a smart phone.The camera module 40 is mounted at a predetermined portion of thecamera-equipped mobile terminal 50. With this structure, a user canshoot using the camera-equipped mobile terminal 50.

Although this example shows by taking as an example in a case of thesmart phone as the camera-equipped mobile terminal 50, thecamera-equipped mobile terminal may be a camera-equipped cellular mobilephone, a notebook personal computer, a tablet-type personal computer, amobile-type game machine, a Web camera, and a vehicle-mounted camera.

Turning back to FIG. 2, the base 12 has a ring-shape which has theoutside shape of rectangular and which has a circular opening portion 12a in the inside thereof. In the example being illustrated, a material ofthe base 12 comprises a material having a high size precision and highheat resistance. Such a material may be, for example, POTICON(registered trademark) of Otsuka Chemical Co. Ltd or a liquid crystalpolymer (LCP).

The lens holder driving device 10 comprises the lens holder 14 includinga tubular portion 140 for holding the lens assembly (the lens barrel) 11(FIG. 5), a ring-shaped driving coil 16 fixed to the lens holder 14 soas to position around the tubular portion 140 thereof, a permanentmagnet 18 opposite to the driving coil 16, an outer yoke 20 comprisingthe permanent magnet 18 at an inner wall surface thereof, an inner yoke30, and a pair of elastic members 22 and 24 disposed to both sides ofthe tubular portion 140 of the lens holder 14 in the direction of theoptical axis O.

A combination of the lens assembly 11 and the lens holder 14 is called alens body. The permanent magnet 18, the outer yoke 20, and the inneryoke 20 constitute a magnetic circuit (18, 20, 30). A combination of themagnetic circuit (18, 20, 30) and the driving coil 18 comprises thedriving portion of the moving coil method.

The pair of elastic members 22 and 24 supports the lens holder 14 in thedirection of the optical axis O shiftably so as to position the lensholder 14 in a radial direction. In the pair of elastic members 22 and24, one elastic member 22 is called an upper elastic member whileanother elastic member 24 is called a lower elastic member. Theillustrated elastic members comprise leaf springs. Accordingly, theupper elastic member 22 is also called an upper leaf spring while thelower elastic member 24 is also called a lower leaf spring.

In addition, in the manner which is described above, in the actual usesituation, the upper direction in the Z-axis direction (the direction ofthe optical axis O) becomes the front direction while the lowerdirection in the Z-axis direction (the direction of the optical axis O)becomes the rear direction. Accordingly, the upper elastic member (theupper leaf spring) 22 is also called a front-side spring while the lowerelastic member (the lower leaf spring) 24 is also called a rear-sidespring.

The upper elastic member (the upper leaf spring; the front-side spring)22 and the lower elastic member (the lower leaf spring; the rear-sidespring) 24 are made, for example, of metal such as a stainless steel ora beryllium copper. In addition, each of the upper elastic member (theupper leaf spring; the front-side spring) 22 and the lower elasticmember (the lower leaf spring; the rear-side spring) 24 is manufacturedby a press working against a predetermined thin plate or an etchingworking using photolithography technique. The etching working isdesirable than the press working. This is because residual stress doesnot remain in the leaf spring in the etching working.

The outer yoke 20 has a rectangular cylindrical shape. Specifically, theouter yoke 20 comprises an outer hollow cylindrical portion 202 havingthe rectangular cylindrical shape and a rectangular outer ring endportion 204 projecting from an upper end (a front end) of the outerhollow cylindrical portion 202 inward. The outer hollow cylindricalportion 202 is also called a shielding yoke.

On the other hand, the driving coil 16 has an octagonal cylindricalshape. More specifically, the driving coil 16 comprises four long sideportions 162 and four short side portions 164 disposed between the fourlong side portions. The tubular portion 140 of the lens holder 14 hasfour bonded surfaces 142 which project in the radial direction outwardat regular spacings of 90 degrees around the optical axis O. To the fourbonded surfaces 142, inner surfaces of the four long side portions 162of the driving coil 16 are bonded by means of adhesives. In addition,the lens holder 14 has, at a lower end portion thereof, an octagonalring-shaped end portion 144 which projects in the radial directionoutward and which is for positioning a bottom portion of the drivingcoil 16.

In the manner which is described above, the lens holder 14 has the fourbonded surfaces 142 for bonding the four areas of the inner surface ofthe driving coil 16 (that are the inner surfaces of the four long sideportions 162 in the example being illustrated) to the tubular portion140 by means of the adhesives (the adhesive resin). In the example beingillustrated, a material of the lens holder 14 comprises a polycarbonate(PC).

On the other hand, the permanent magnet 18 comprises four permanentmagnet pieces 182 each of which has a substantially triangular pillarshape and which are disposed opposite to the short long side portions164 of the driving coil 16. The four permanent magnet pieces 182 aredisposed to inner walls at four corners of the outer hollow cylindricalportion (the shielding yoke) 202 of the outer yoke 20. In addition, inactuality, each permanent magnet piece 182 is a trapezoid in crosssection in a direction orthogonal to the direction of the optical axisO.

In the manner which is described above, the permanent magnet 18comprises the four permanent magnet pieces 182 each having thesubstantially triangular pillar shape that are mounted to the fourcorners of the outer hollow cylindrical portion (the shielding yoke) 202of the outer yoke 20. The outer ring-shaped end portion 204 has anopening 204 a.

As shown in FIG. 4, at the inner surfaces of the four corners of theouter hollow cylindrical portion (the shielding yoke) 202 of the outeryoke 20, the permanent magnet 18 is disposed with a space between it andthe driving coil 16.

The upper elastic member (the upper leaf spring; the front-side spring)22 is disposed at an upper side (a front side) of the lens holder 14 inthe direction of the optical axis O while the lower elastic member (thelower leaf spring; the rear-side spring) 24 is disposed at a lower side(a rear side) of the lens holder 14 in the direction of the optical axisO.

More specifically, the upper elastic member (the upper leaf spring; thefront-side spring) 22 comprises an inner end portion 222 mounted on thelens holder 14 and an outer end portion 224 mounted on the outer yoke 20via a spacer 28 in the manner which will later be described. Between theinner end portion 222 and the outer end portion 224, four arm portions226 are provided. Each arm portion 226 connects the inner end portion222 to the outer end portion 224.

On the other hand, the lower elastic member (the lower leaf spring; therear-side spring) 24 comprises an inner end portion 242 mounted on thelens holder 14 at a lower end thereof and an outer end portion 244mounted on the base 12 in the manner which will later be described.Between the inner end portion 242 and the outer end portion 244, fourarm portions 246 are provided. Each arm portion 246 connects the innerend portion 242 to the outer end portion 244.

In addition, the inner end portion is also called an inner ring whilethe outer end portion is also called an outer ring.

The inner end portion 222 of the upper elastic member (the upper leafspring; the front-side spring) 22 is fixed to the upper end of the lensholder 14. On the other hand, the outer end portion 224 of the upperelastic member (the upper leaf spring; the front-side spring) 22 isadhesively fixed to the outer yoke 20 via the spacer 28. In the examplebeing illustrated, a material of the spacer 28 comprises a polycarbonate(PC).

In the example being illustrated, the upper elastic member (the upperleaf spring; the front-side spring) 22 is disposed between the spacer 28and the inner yoke 30. The inner yoke 30 is also called a counter yokeor a back yoke. In addition, these three parts are integrated as onestructure (22, 28, 30) by heat-welding in the manner which will later bedescribed.

More specifically, the spacer 28 has a rectangular ring shape which hasan opening portion 28 a at a central portion thereof. The spacer 28comprises four protrusions 282 which project at four corners thereofupward. These four protrusions 282 serve as heat-welding portions in themanner which will later be described. The outer end portion 224 of theupper elastic member (the upper leaf spring; the front-side spring) 22has four through holes 224 a through which the four protrusions 282 ofthe spacer pass.

On the other hand, the inner yoke (the counter yoke; the back yoke) 30comprises a rectangular ring-shaped inner ring end portion 302 mountedto an inner wall of the outer hollow cylindrical portion 202 of theouter yoke 20 at an upper end side thereof and four vertical extendingportions 304 which extend in parallel with the optical axis O verticallydownwards at the inside of four corners of the inner ring end portion302. The inner ring end portion 302 has four fitting holes 302 a inwhich the four protrusions 282 of the spacer 28 fit.

Accordingly, as shown in FIG. 4, the above-mentioned structure (22, 28,30) is assembled by fitting the four protrusions 282 of the spacer 29 inthe four fitting holes 302 a of the inner ring end portion 302 of theinner yoke 30 through the four through holes 224 a of the outer endportion 224 of the upper elastic member 22 and by heat-welding tips ofthe four protrusions 282. The structure (22, 28, 30) is mounted to theinner wall surface of the outer yoke 20 by means of adhesive.

As shown in FIG. 4, by the above-mentioned heat-welding, heat-weldedportions 282 a are formed at the respective tips of the four protrusions282 of the spacer 28. By the heat-welded portions 282 a, the fourpermanent magnet pieces 182 are positioned. In other words, the innerring end portion 302 of the inner yoke 30 and the permanent magnet 18are apart from each other by the head-welded portions 282 a.

In addition, the inner ring end portion 302 of the inner yoke 30 hashollow portions 302 b at four outer sides thereof. This is forfacilitating to insert the above-mentioned structure (22, 28, 30) in theouter yoke 30.

Although mounting (fixing) of the structure (22, 28, 30) to the outeryoke 20 is carried out by adhesive in the example being illustrated, themounting (the fixing) may be carried out by laser welding orheat-welding. Herein, in “the laser welding”, the structure (22, 28, 30)is fused to the inner wall surface of the outer yoke 20 by irradiatinglaser light to the outer ring-shaped end portion 204 of the outer yoke20 from the outside. In “the heat-welding”, the structure (22, 28, 30)is mounted to the outer yoke 20 by forming, in the spacer 28, aplurality of protrusions projecting upwards, by forming, in the outerring-shaped end portion 204 of the outer yoke 20, a plurality of holesin which the plurality of protrusions are inserted, and by heat-weldingtips of the plurality of protrusions.

Inasmuch as the upper elastic member 22 is heat-welded to the spacer 28in this exemplary embodiment in the manner which is described above, itis possible to easily mount the upper elastic member 22 to the outeryoke 20 and it is possible to easily position the upper elastic member22 with respect to the outer yoke 20.

In addition, a yoke comprises the outer yoke 20 and the inner yoke 30 inthis exemplary embodiment. It is therefore advantageous in that itincreases flexibility in design of the yoke. In addition, inasmuch asthe inner yoke (the counter yoke; the back yoke) 30 is mounted to theinner wall of the outer hollow cylindrical portion of the outer yoke 20,it is possible to easily assemble the lens holder driving device 10.

In the manner which is described above, the inner end portion 242 of thelower elastic member (the lower leaf spring; the rear-side spring) 24 isfixed to a lower end side of the lens holder 14. On the other hand, theouter end portion 244 of the lower elastic member (the lower leafspring; the rear-side spring) 24 is fixed to the base 12.

More specifically, the base 12 has the rectangular ring shape which hasthe circular opening portion 12 a at the central portion thereof, in themanner described above. The base 12 comprises four protrusions 122 whichproject at four corners thereof upward. The outer end portion 244 of thelower leaf spring 24 has four fitting holes 224 a in which the fourprotrusions 122 fit.

As show in FIGS. 21 and 23, the tubular portion 140 of the lens holder14 has an inner wall in which a female screw thread 14 a is cut. On theother hand, as shown in FIG. 5, the lens assembly (the lens barrel) 11has an outer wall in which a male screw thread 11 a screwed in theabove-mentioned female screw thread 14 a is cut. In a case of fittingthe lens assembly (the lens barrel) 11 to the lens holder 14, itincludes the steps of rotating the lens assembly (the lens barrel) 11with respect to the tubular portion 140 of the lens holder 14 around theoptical axis O to screw it along the direction of the optical axis Othereby accommodating the lens assembly (the lens barrel) 11 in the lensholder 14, and of connecting them to each other via an adhesive agent orthe like.

Turning back to FIG. 2, the lens holder driving device 10 comprisesfirst and second electrode terminals 32-1 and 32-2 which are forsupplying the driving coil 16 with power. The base 12 has a pair ofinsertion holes 12 b for inserting and setting the first and the secondelectrode terminals 32-1 and 32-2. In addition, the lower elastic member(the lower leaf spring; the rear-side spring) 24 comprises first andsecond leaf spring pieces 24-1 and 24-2 which are electrically insulatedto each other. The first and the second electrode terminals 32-1 and32-2 are electrically connected to the first and the second leaf springpieces 24-1 and 24-2 by means of solder 38 (see, FIG. 24), respectively.In addition, the first and the second leaf spring pieces 24-1 and 24-3are electrically connected to first and second end portions 16-1 and16-2 of the driving coil 16 by means of solder 36 (see, FIG. 21),respectively.

Accordingly, by energizing the driving coil 16 via the first and thesecond leaf spring pieces 24-1 and 24-2 from the first and the secondelectrode terminals 32-1 and 32-2, it is possible to positionally adjustthe lens holder 14 (the lens assembly 11) in the direction of theoptical axis O according to interaction between a magnetic field of thepermanent magnet 18 and a magnetic field due to an electric currentflowing through the driving coil 16.

In the above-mentioned lens holder driving device 10, a combination ofthe lens holder 14 for holding the lens assembly 11 and the driving coil16 serves as a pillar movable portion (14, 16) disposed in a centralportion. In addition, a combination of the base 12, the permanent magnet18, the outer yoke 20, the spacer 28, and the inner yoke 30 acts as atubular fixed portion (12, 18, 20, 28, 30) disposed around the movableportion (14, 16).

Referring now to FIGS. 8 through 14, the description will proceed tostoppers in the up-and-down direction Z of the lens holder 14. FIG. 8 isa bottom view of the outer yoke 20 while FIG. 9 is a plan view of thelens holder 14. FIG. 10 is a side view of the lens holder 14. FIG. 11 isa bottom view of the lens holder 14 while FIG. 12 is a plan view of thebase 12. FIG. 13 is an explanation view showing stopper locationsbetween the outer yoke 20 and the lens holder 14 while FIG. 14 is anexplanation view showing stopper locations between the lens holder 14and the base 12.

As shown in FIG. 8, the outer ring end portion 204 of the outer yoke 20has four yoke projections 204-1 each of which projects in the radialdirection inwards. On the other hand, as shown in FIG. 9, the tubularportion 140 of the lens holder 14 has four holder upper projections 146each of which projects upwards from an upper end thereof.

As shown in FIG. 13, when the lens holder 14 moves upwards, the fourholder upper projections 146 engage with and stop at the correspondingfour yoke projections 204-1 of the outer yoke 20, respectively. That is,the four yoke projections 204-1 of the outer yoke 20 act as an upperstopper (engaging/stopping member) for restricting an upward movement ofthe lens holder 14.

As shown in FIG. 12, the base 12 has four base projections 124 each ofwhich projects upward at a circumference of the circular opening portion12 a. On the other hand, as shown in FIG. 11, the ring-shaped endportion 144 of the lens holder 14 has four holder lower projections 148each of which projects downward.

As shown in FIG. 14, when the lens holder 14 moves downward, the fourholder lower projections 148 engage with and stop at the correspondingfour base projections 124 of the base 12, respectively. That is, thefour base projections 124 of the base 12 serve as a lower stopper(engaging/stopping member) for restricting a downward movement of thelens holder 14.

Referring now to FIGS. 15 through 20, the description will proceed to arotation restricting mechanism of the lens holder 14. FIG. 15 is aperspective view of the inner yoke 30 while FIG. 16 is a perspectiveview of the lens holder 14. FIG. 17 is a transverse sectional view of anassembly into which the inner yoke 30 and the lens holder 14 areassembled. FIG. 18 is a perspective view of the lens holder 14 whileFIG. 19 is a perspective view of the base 12. FIG. 20 is a transversesectional view of an assembly into which the lens holder 14 and the base12 are assembled.

First, referring to FIGS. 15 through 17, the description will proceed toa top rotation restricting mechanism of the lens holder 14.

As shown in FIG. 15, the four vertical extending portions 304 of theinner yoke 30 have inner wall surfaces 304 a. On the other hand, asshown in FIG. 16, the tubular portion 140 of the lens holder 14 has fourouter wall surfaces 140 a opposed to the inner wall surfaces 304 a ofthe four vertical extending portions 304 with a predetermined spacingleft therebetween.

Accordingly, when the lens holder 14 is about to rotate with respect tothe inner yoke 30 around the optical axis O as shown in FIG. 17, theinner wall surfaces 304 a of the four vertical extending portions 304 ofthe inner yoke 30 come into contact with the four outer wall surfaces140 a of the tubular portion 140 of the lens holder 14 at positionsshown in A of FIG. 17, and it results in restricting the rotation of thelens holder 14.

Next, referring to FIGS. 18 through 20, the description will proceed toa bottom rotation restricting mechanism of the lens holder 14.

As shown in FIG. 18, the tubular portion 140 of the lens holder 14 hasfour engagement protrusions 149 projecting in a radial directionoutwards from a lower end thereof. On the other hand, as shown in FIG.19, the base 12 has, at a circumference of the circular opening portion12 a, four engagement grooves 12 c in which the four engagementprotrusions 149 are freely fitted, respectively.

Accordingly, when the lens holder 14 is about to rotate with respect tothe base 12 around the optical axis O as shown in FIG. 20, the fourengagement protrusions 149 of the lens holder 14 engage with the fourengagement grooves 12 c of the base 12 at positions shown in B of FIG.20, and it results in restricting the rotation of the lens holder 14.

Referring now to FIGS. 21 and 22, the description will proceed to amethod of electrically connecting the lower elastic member (the lowerleaf spring; the rear-side spring) 24 with the driving coil 16.

FIG. 21 is a perspective view of the lower elastic member (the lowerleaf spring; the rear-side spring) 24 disposed in the lens holder 14 atthe lower end thereof seen from a slanting below. FIG. 22 is a partialenlarged perspective view enlargedly showing an area where the secondleaf spring piece 24-2 of the lower elastic member (the lower leafspring; the rear-side spring) 24 in FIG. 21 is soldered to the secondend portion 16-2 of the driving coil 16 by means of the solder 36.

As shown in FIG. 21, the ring-shaped end portion 144 of the lens holder14 has six lower projections 144 a projecting outwards. On the otherhand, as shown in FIG. 2, the inner end portion 242 of the lower elasticmember 24 has six lower holes 242 a in which the six lower projections144 a are pressured and inserted (slipped and mounted), respectively.That is, the six lower projections 144 a of the ring-shaped end portion144 of the lens holder 14 are pressured and inserted (slipped andmounted) in the six lower holes 242 a of the inner end portion 242 ofthe lower elastic member 24, respectively.

In addition, the first and the second leaf spring pieces 24-1 and 24-2of the lower elastic member (the lower leas spring; the rear-sidespring) 24 have, at the inner end portions 242 thereof, first and secondside portions 242-1 and 242-2 for electrically connecting to the firstand the second end portions 16-1 and 16-2 of the driving coil 16 bymeans of the solder 26, respectively. The first and the second sideportions 242-1 and 242-2 are disposed in the vicinity of the ring-shapedend portion 144 of the lens holder 14.

As shown in FIG. 22, the second side portion 242-2 has a side edgeforming portion 242-2 a having a side surface which is subjected with ahalf etching. By the half etching of the side edge forming portion 242-2a, the side surface of the second side portion 242-2 has an oxide filmformed thereon that is removed and has large surface roughness. In otherwords, by subjecting the side edge forming portion 242-2 a with the halfetching, edges (edge portions) are formed in the second side portion242-2 and suitability of the second side portion 242-2 to be soldered bymeans of the solder 36 is favorable (is improved), as shown in FIG. 21.

Although illustration is not made, the first side portion 242-1 also hasa side edge forming portion having a side surface which is subjectedwith a half etching. As a result, in the manner which is describedabove, suitability of the first side portion 242-1 to be soldered bymeans of the solder 36 is also favorable (is improved).

Inasmuch as the first and the second side portions 242-1 and 242-2 havethe side edge forming portions 242-2 a having the side surfacessubjected with the half etching in the manner which is described above,it is possible to shorten a time interval required while heat is addedto the lens holder 14 upon soldering by means of the solder 36. As aresult, it is possible to prevent the lens holder 14 from deforming dueto heat.

Referring to FIGS. 23 through 25, the description will proceed to amethod of electrically connecting the lower elastic member (the lowerleaf spring; the rear-side spring) 24 with the first and the secondelectrode terminals 32-1 and 32-2.

FIG. 23 is a perspective view showing a state where the outer yoke 20,the spacer 28, the upper electric member (the upper leaf spring; thefront-side spring) 22, and the inner yoke 30 are removed from the lensdriving device 10. FIG. 24 is a partial enlarged perspective viewenlargedly showing a part where the first leaf spring piece 24-1 of thelower elastic member (the lower leaf spring; the rear-side spring) 24 inFIG. 23 is electrically connected to the first electrode terminal 32-1by means of the solder 38. FIG. 25 is a partial enlarged perspectiveview enlargedly showing a connected portion between the first leafspring piece 24-1 and the first electrode terminal 32-1 before solderingby means of the solder 38 in FIG. 24.

As shown in FIG. 23, the module board 34 is disposed in the lowerportion (the rear portion) of the base 12 in the manner which isdescribed above. The printed circuit board (PCB) including the imagepickup device 13 (see, FIG. 6) is mounted to the base 12 through themodule board 34, in the manner which is described above. The base 12 andthe module board 34 are integrated to each other.

As shown in FIG. 23, the first and the second leaf spring pieces 24-1and 24-2 of the lower elastic member 24 have, at the outer end portions244 thereof, first and second terminal connection portions 244-1 and244-2 which are electrically connected to the first and the secondelectrode terminals 32-1 and 32-2, respectively. The first and thesecond terminal connection portions 244-1 and 244-2 are mounted on thebase 12.

As shown in FIG. 25, the first terminal connection portion 244-1 has aconnection edge forming portion 244-1 a having a connection surfacesubjected with a half etching. By the half etching of the connectionedge forming portion 244-1 a, the connection surface of the firstterminal connection portion 244-1 has an oxide film formed thereon thatis removed and has large surface roughness. In other words, bysubjecting the connection edge forming portion 244-1 a with the halfetching, edges (edge portions) are formed in the first terminalconnection portion 244-1 and suitability of the first terminalconnection portion 244-1 to be soldered by means of the solder 38 isfavorable (is improved), as shown in FIG. 24.

Although illustration is not made, the second terminal connectionportion 244-2 also has a connection edge forming portion having aconnection surface which is subjected with a half etching. As a result,in the manner which is described above, suitability of the secondterminal connection portion 244-2 to be soldered by means of the solder38 is also favorable (is improved).

Inasmuch as the first and the second terminal connection portions 244-1and 244-2 have the connection edge forming portions 244-1 a having theconnection surfaces subjected with the half etching in the manner whichis described above, it is possible to shorten a time interval requiredwhile heat is added to the base 12 upon soldering by means of the solder38. As a result, it is possible to prevent the base 12 from deformingdue to heat.

In addition, in this exemplary embodiment, as shown in FIG. 25, thefirst electrode terminal 32-1 has a terminal edge forming portion 32-1 ahaving a terminal surface, at a part connected to the first terminalconnection portion 244-1, subjected with a half etching. By the halfetching of the terminal edge forming portion 32-1 a, the terminalsurface of the first electrode terminal 32-1 has an oxide film formedthereon that is removed and has large surface roughness. In other words,by subjecting the terminal edge forming portion 32-1 a with the halfetching, edges (edge portions) are formed in the first electrodeterminal 32-1 and suitability of the first electrode terminal 32-1 to besoldered by means of the solder 38 is favorable (is improved), as shownin FIG. 24.

Although illustration is not made, the second electrode terminal 32-2also has a terminal edge forming portion having a terminal surface, at apart connected to the second terminal connection portion 244-2,subjected with a half etching. As a result, in the manner which isdescribed above, suitability of the second electrode terminal 32-2 to besoldered by means of the solder 38 is also favorable (is improved).

Inasmuch as the first and the second electrode terminals 32-1 and 32-2have the terminal edge forming portions 32-1 a having the terminalsurfaces subjected with the half etching in the manner which isdescribed above, it is possible to shorten a time interval requiredwhile heat is added to the base 12 upon soldering by means of the solder38. As a result, it is possible to prevent the base 12 from deformingdue to heat.

While this invention has been particularly shown and described withreference to the exemplary embodiment thereof, the invention is notlimited to the embodiment. It will be understood by those of ordinaryskill in the art that various changes in form and details may be thereinwithout departing from the spirit and scope of the present invention asdefined by the claims.

For example, although the description has been made by taking, as anexample, a case of subjecting with the half etching as the edge formingportion in the above-mentioned exemplary embodiment, the edge formingportion is not limited to one subjecting with the half etching and maybe any shape where the edges are formed. As an example, the edge formingportion may be a hole or holes.

The whole or part of the exemplary embodiments disclosed above can bedescribed as, but not limited to, the following supplementary notes.

(Supplementary note 1) A lens holder driving device (10) comprising:

a lens holder (14) in which a lens assembly (11) is mounted;

a driving coil (16) fixed to said lens holder (14) at outsidecircumference thereof, said driving coil (16) having first and secondend portions (16-1, 16-2);

a magnet (18) opposite to said driving coil (16);

a yoke (20, 30) including said magnet (18);

an elastic member (22, 24) supporting said lens holder (14) in adirection of an optical axis (O) of said lens assembly (11) shiftably;and

a base (12) disposed at a lower side of said lens holder (14),

wherein said elastic member (22, 24) comprises a lower elastic member(24) disposed at a lower side of said lens holder (14), said lowerelastic member (24) comprising first and second leaf spring pieces(24-1, 24-2) into which said lower elastic member (24) is divided,

wherein said first and second leaf spring pieces (24-1, 24-2) have firstand second side portions (242-1, 242-2) which are electrically connectedto the first and second end portions (16-1, 16-2) of said driving coil(16) by soldering (36), respectively, and

wherein each of said first and second side portions (242-1, 242-2) has aside edge forming portion (242-2 a) having a side surface in which edgesare formed.

(Supplementary note 2) The lens holder driving device (10) according toSupplementary note 1, wherein said side edge forming portion (242-2 a)comprises a part in which the side surface is subjected with a halfetching.

(Supplementary note 3) The lens holder driving device (10) according toSupplementary note 1, wherein said base (12) mounts an image pickupdevice (13) thereon.

(Supplementary note 4) A camera (50) in which the lens holder drivingdevice (10) according to Supplementary note 3 is mounted.

(Supplementary note 5) A lens holder driving device (10) comprising: alens holder (14) in which a lens assembly (11) is mounted; a drivingcoil (16) fixed to said lens holder (14) at outside circumferencethereof;

a magnet (18) opposite to said driving coil (16);

a yoke (20, 30) including said magnet (18);

an elastic member (22, 24) supporting said lens holder (14) in adirection of an optical axis (O) of said lens assembly (11) shiftably;and

a base (12) disposed at a lower side of said lens holder (14),

wherein said elastic member (22, 24) comprises a lower elastic member(24) disposed at a lower side of said lens holder (14), said lowerelastic member (24) comprising first and second leaf spring pieces(24-1, 24-2) into which said lower elastic member is divided,

wherein said lens holder driving device (10) further comprises first andsecond electrode terminals (32-1, 32-2) for feeding said driving coil(16) via said first and second leaf spring pieces (24-1, 24-2),

wherein said first and second leaf spring pieces (24-1, 24-2) have firstand second terminal connection portions (244-1, 244-2) which areelectrically connected to said first and second electrode terminals(32-1, 32-2) by soldering (38), respectively, and

wherein each of said first and second terminal connection portions(244-1, 244-2) has a connection edge forming portion (244-1 a) having aconnection surface in which edges are formed.

(Supplementary note 6) The lens holder driving device (10) according toSupplementary note 5, wherein said connection edge forming portion(244-1 a) comprises a part in which the connection surface is subjectedwith a half etching.

(Supplementary note 7) The lens holder driving device (10) according toSupplementary note 5, wherein said first and second electrode terminals(32-1, 32-2) have terminal edge forming portions (32-1 a) havingterminal surfaces in which edges are formed at parts connected to saidfirst and second terminal connection portions (244-1, 244-2),respectively.

(Supplementary note 8) The lens holder driving device (10) according toSupplementary note 7, wherein said terminal edge forming portions (32-1a) comprise parts in which the terminal surfaces are subjected with ahalf etching.

(Supplementary note 9) The lens holder driving device (10) according toSupplementary note 5, wherein said base (12) mounts an image pickupdevice 13) thereon.

(Supplementary note 10) A camera (50) in which the lens holder drivingdevice according to Supplementary note 9 is mounted.

In this connection, inasmuch as reference symbols in parentheses areattached in order to facilitate an understanding of this invention andare merely one example thereof, this invention is, of course, notlimited to them.

What is claimed is:
 1. A lens holder driving device comprising: a lensholder in which a lens assembly is mounted; a driving coil fixed to saidlens holder at outside circumference thereof, said driving coil havingfirst and second end portions; a magnet opposite to said driving coil; ayoke including said magnet; an elastic member supporting said lensholder in a direction of an optical axis of said lens assemblyshiftably; and a base disposed at a lower side of said lens holder,wherein said elastic member comprises a lower elastic member disposed ata lower side of said lens holder, said lower elastic member comprisingfirst and second leaf spring pieces into which said lower elastic memberis divided, wherein said first and second leaf spring pieces have firstand second side portions which are electrically connected to the firstand second end portions of said driving coil by soldering, respectively,and wherein each of said first and second side portions has a side edgeforming portion having a side surface in which edges are formed.
 2. Thelens holder driving device as claimed in claim 1, wherein said side edgeforming portion comprises a part in which the side surface is subjectedwith a half etching.
 3. The lens holder driving device as claimed inclaim 1, wherein said base mounts an image pickup device thereon.
 4. Acamera in which the lens holder driving device as claimed in claim 3 ismounted.
 5. A lens holder driving device comprising: a lens holder inwhich a lens assembly is mounted; a driving coil fixed to said lensholder at outside circumference thereof; a magnet opposite to saiddriving coil; a yoke including said magnet; an elastic member supportingsaid lens holder in a direction of an optical axis of said lens assemblyshiftably; and a base disposed at a lower side of said lens holder,wherein said elastic member comprises a lower elastic member disposed ata lower side of said lens holder, said lower elastic member comprisingfirst and second leaf spring pieces into which said lower elastic memberis divided, wherein said lens holder driving device further comprisesfirst and second electrode terminals for feeding said driving coil viasaid first and second leaf spring pieces, wherein said first and secondleaf spring pieces have first and second terminal connection portionswhich are electrically connected to said first and second electrodeterminals by soldering, respectively, and wherein each of said first andsecond terminal connection portions has a connection edge formingportion having a connection surface in which edges are formed.
 6. Thelens holder driving device as claimed in claim 5, wherein saidconnection edge forming portion comprises a part in which the connectionsurface is subjected with a half etching.
 7. The lens holder drivingdevice as claimed in claim 5, wherein said first and second electrodeterminals have terminal edge forming portions having terminal surfacesin which edges are formed at parts connected to said first and secondterminal connection portions, respectively.
 8. The lens holder drivingdevice as claimed in claim 7, wherein said terminal edge formingportions comprise parts in which the terminal surfaces are subjectedwith a half etching.
 9. The lens holder driving device as claimed inclaim 5, wherein said base mounts an image pickup device thereon.
 10. Acamera in which the lens holder driving device as claimed in claim 9 ismounted.